Rhubey Posted June 15, 2012 Share Posted June 15, 2012 Hi! I have a 2002 Outback Wagon 5speed with 145k miles on it. Recently it has been "hopping" when taking off from a full stop if the ac is on. It seems to only be in the lower gears that I have this problem, and simply poking the ac button off untill I reach highway speed seems to fix it. It isn't the worst problem in the world, but I worry about getting rear ended if I can't out of the way in a hurry. What should I start hitting with a hammer first? In all seriousness, I am in Florida and don't know of any local shops that are knowledgeable with Roos, and I always worry about getting ripped off due to my lack of technical abilities. Thanks for any help you can suggest. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 15, 2012 Share Posted June 15, 2012 slow auto tranny engagement? I dunno, probably try doing 3 drain/refill/drive cycles with transmission fluid if it hasn't been changed in a while/ever. Quote Link to comment Share on other sites More sharing options...
Rhubey Posted June 15, 2012 Author Share Posted June 15, 2012 Thank you for replying. Apologies for my ignorance, but I have never heard of changing transmission fluid in a 5 speed. Should that be done often? Is it difficult? How is it that air conditioning and my clutch would affect each other? I should warn you I have almost no experience with working on cars. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 15, 2012 Share Posted June 15, 2012 (edited) Thank you for replying. Apologies for my ignorance, but I have never heard of changing transmission fluid in a 5 speed. Should that be done often? Is it difficult? How is it that air conditioning and my clutch would affect each other? I should warn you I have almost no experience with working on cars. oops! You did say 5-speed. sorry, completely my mistake. When you use the term 'hopping' - is it a jerking motion during/after clutch engagement? Cars are built to boost idle speed when the A/C (and maybe some other) load is presented to the engine. Clutches are also wear items - similar to the material used on brakepads. Any change between the way these systems work might lead to an odd change in take-off like you have started experiencing. If this problem is new, it's difficult to fault your driving style so, I can only suggest there has been a change in either the clutch or the way the idle is boosted by the ECU. Sometimes even throttlebody cleaning will help issues like this but that seems less likely. It may be time to have a good mechanic check for clutch wear/problems and proper idle adjustment when the A/C is engaged. Edited June 15, 2012 by 1 Lucky Texan Quote Link to comment Share on other sites More sharing options...
Rhubey Posted June 15, 2012 Author Share Posted June 15, 2012 By hopping I mean a full out bounce. Like as though I was repeatedly quickly pushing in the clutch and letting it out carelessly. The whole car nosedives and then jerks back up repeatedly. It happens in 1-3rd gear right after letting out the clutch and instantly stops if I depress the clutch pedal or shut off the AC. I have been driving stickshifts for 15 years so I know to be gentle. The change that happened that made me notice the problem is this: it got hot outside so I started using my AC. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 15, 2012 Share Posted June 15, 2012 when you're idling (clutch in or neutral), if you cycle the a/c on-off, how much, if any, does the RPM change? Quote Link to comment Share on other sites More sharing options...
Rhubey Posted June 15, 2012 Author Share Posted June 15, 2012 When I first started my car it idled just over 1k. I tapped the gas then let off and then it went to 1k on the dot. Flipped on the ac, it went up to about 1100 then I heard the click as the compressor kicked on. Idle then dropped to just below 1k. Turned off ac and idle fell Way low. Like 750. Then I turned ac back on. RMP flew back up to just above 1k, then creeped back to just below 1k in about 10 seconds. Turned ac off again, it bogged down again. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 15, 2012 Share Posted June 15, 2012 that doesn't 'seem' unreasonable - maybe someone else will have some ideas. was there a wreck, modification or any work done to the car before this symptom appeared? Quote Link to comment Share on other sites More sharing options...
Rhubey Posted June 15, 2012 Author Share Posted June 15, 2012 No wrecks or modifications. The ac wasn't blowing super cold so I added some a few weeks ago, but the problem did not start right after that. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 16, 2012 Share Posted June 16, 2012 (edited) I'm no expert on the exact symptoms, but some folks have had a bad 'rpm sensor' in the a/c compressor on some outbacks - problem is, I THINK it's older models than yours - not sure. it just seems that compressor load on the engine through the belt is the most likely source of the problem. How does the a/c work idling? Is it blowing cold with no weird noises or problems? try searching on rpm sensor and a/c and see what turns up. not much help I know, maybe someone else will have an idea. Edited June 16, 2012 by 1 Lucky Texan Quote Link to comment Share on other sites More sharing options...
uniberp Posted June 16, 2012 Share Posted June 16, 2012 No wrecks or modifications. The ac wasn't blowing super cold so I added some a few weeks ago, but the problem did not start right after that. You may have overfilled it. A/C systems are generally designed to automatically shift off during heavy acceleration. I don't know the circuitry but it seems it would come from the ecu/tcu. The compressor may also be failing and you may be burning up the ac clutch. Old ac simply doesn not work as well as new, and rebuilt compressors and expansion valves never seem to be as good as new. I always go for the bargain ones, however. Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 18, 2012 Share Posted June 18, 2012 Let me guess you have a 5 MT? I used to drive only auto Subaru's and I never noticed this problem.. but my last two have been manuals and yes you can feel when the AC kicks in.. it's really annoying in low speed traffic to have it kick in and the car will jerk because of it. I always thought they were crazy at NASIOC saying they could feel the AC kick in at highway speed.. but it's true. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted June 18, 2012 Share Posted June 18, 2012 Classic low RPM Misfire. Plugs and wires would likely do it some good. NGK or Subaru OE wires ONLY. Cheap out on plug wires and you'll be jumping out of the pan and into the fire, so to speak. Buy the plugs that are recommended in the Owners manual or emission sicker under the hood if it says. (some say which plugs the engine is supposed to have some don't) These can be a little jumpy, but that's a slow onset symptom. It sounds as if it was doing fine one day then started doing this the next? Quote Link to comment Share on other sites More sharing options...
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